IceTray

Just finished doing an entire rebuild of a 96' LT1 Camaro. Rebuilt the LT1 and a portion of the T56 that's on there now. After getting on it, the rear main seal went bad (after the water pump, of course) so now I have to drop the transmission to fix that.

I want to go back to automatic transmission because of this city traffic, it's a lot of stop and go, and just isn't friendly towards a standard.

Now, I have a 1995 Corvette computer, which was automatic off an LT1, and there's a few 4l60e transmissions in the area I can grab easily, which should bolt right on to this current LT1 I have.

What exactly would be required to get the 4l60e to run properly? Will the 95PCM from the vette run it no problem, or will I need to replace the entire wire harness? I also hear the trans would need an external cooler, even though the rad is setup to cool the trans already.

Edit: a local scrap yard has a 1995 3.4l v6 with the 4l60e, but they said the inside of the V6 and V8 4l60e are completely different, and it won't up to the power of the V8 - I can't confirm that or not, because I was previously told otherwise.

mrvedit

The '94 and '95 were oddball and unique years. You need to match those year to the same year PCM. ('96 through about '06 are all electrically compatible.)

The only difference between a 4L60E from a V6 and a V8 is the shift firmness determined by the size of the holes in the separator plate and perhaps the accumulator springs. These are all relatively easily changed. Contrary to what your JY said, the internals are identical and the strength is identical.

Keep in mind that any trans from a JY might already be worn out or have only a few miles left on it. Since (especially the early) 4L60E has various weak spots, I would be more inclined to get a 4L60E from a V6 as it is less likely to have been abused.

I would likely install the "Vette servo" too, a $15 part. A new separator plate, drilled for a V8 (or performance V8) could easily be installed by a trans shop for about 2 hours labor, $50 in parts plus fluid and filter.

IceTray

So, the 4l60e they have at the yard is off an accident car, front end collision. Says the tranny has about 165,000km on it. This thing literally only needs to last about a year or two, no hard runs or anything - then it'll be swapped for the 4l80e, it's just too pricey for me to do right now.

They've also got a 96 Camaro V8 computer, which should hook up no problems.

Let's say I grab this 4l60e and compatible year computer. They should in theory just bolt right up, correct? I know with the 4l80e I need a yoke, but again I've heard mixed reviews about going from T56 to 4l60e.

Found a detailed walk through on the vette servo, appreciate that little tidbit of info. I took a quick peek around for the separator plates and they mostly seem to be on ebay, any particular source to get a V8 setup?

mrvedit

I don't anything about LT1 engines or cars, just the details on the 4L60E.

The separator plate you want is the Transgo part # 46-96-PLT; $20 at Summit Racing. Then follow the instructions to drill it for a V8.

IceTray

Fair enough. I appreciate the info you've provided though.

I guess for everyone else my question would be, is the wire harness the same between the manual and automatic? Can I hook up a manual wire harness to an automatic computer and trans? Will there be anything missing, or are there different ground wires that could fry everything?

bbond105

This web site may help.
http://www.lt1swap.com/wiringharness.htm

IceTray

So finding a 1995 wire harness to control the 4l60e with the 1995 computer is next to impossible right now. I've found 93, 94, 96, 97, etc.

Now, I already have a wire harness connected to the T56, albeit a 1996 wire harness. Is there any way to change this harness to control the 4l60e using the 1995 computer?

mrvedit

What about buying a '96 computer? I doubt it is more than $100.
You could then use any '96 through '07 4L60E/4L65E/4L70E; later model transmissions are stronger - some improvements were made in '98 for the LS1 and more improvements in '03 for the LS2.

IceTray

I can probably source a 96 computer.
The trans is from a 95 camaro though. It should run it, but I'd still need a wire harness. I did find someone who has a 95 harness, however he cut off all the wires for emissions, but still has them. So as long as the base of that harness works, it should control the trans.

I should have it late this week, so ill chime in then and let you know how it goes.

My only other question though.
The car has the third pedal for the clutch. Do I have to remove that pedal to use the 4l60e + harness? Or will I still need to clutch to ignition?

mrvedit

Sorry, I forgot you also have the '95 trans which requires a '95 PCM. (I'm posting on many threads and mixing things up a bit.)
The harness without emission wires should be fine. Probably more than you want to spend, but I know at least one company that could make a custom harness for around $500.
The clutch "safety switch" wiring can be moved to the trans - possibly to the shifter. The thirdgen.org forum might have better info on this.

IceTray

Oh yeah, forgot the 95 was its own beast.
Just for sh*ts and giggles, whats the company that can produce a harness for $500?

Turns out the fella with the harness that I thought was a mangled 95 is actually a 97, which I dont believe will work properly, if I'm correct.